diff --git a/examples/starwars_relay/tests/snapshots/snap_test_objectidentification.py b/examples/starwars_relay/tests/snapshots/snap_test_objectidentification.py
index d7694e90..b02a420c 100644
--- a/examples/starwars_relay/tests/snapshots/snap_test_objectidentification.py
+++ b/examples/starwars_relay/tests/snapshots/snap_test_objectidentification.py
@@ -115,5 +115,4 @@ input IntroduceShipInput {
   shipName: String!
   factionId: String!
   clientMutationId: String
-}
-'''
+}'''
diff --git a/examples/starwars_relay/tests/test_objectidentification.py b/examples/starwars_relay/tests/test_objectidentification.py
index f280df04..c024f432 100644
--- a/examples/starwars_relay/tests/test_objectidentification.py
+++ b/examples/starwars_relay/tests/test_objectidentification.py
@@ -9,7 +9,7 @@ client = Client(schema)
 
 
 def test_str_schema(snapshot):
-    snapshot.assert_match(str(schema))
+    snapshot.assert_match(str(schema).strip())
 
 
 def test_correctly_fetches_id_name_rebels(snapshot):
diff --git a/graphene/relay/tests/test_node.py b/graphene/relay/tests/test_node.py
index d46838ac..6b310fde 100644
--- a/graphene/relay/tests/test_node.py
+++ b/graphene/relay/tests/test_node.py
@@ -1,7 +1,7 @@
 import re
-from graphql_relay import to_global_id
+from textwrap import dedent
 
-from graphene.tests.utils import dedent
+from graphql_relay import to_global_id
 
 from ...types import ObjectType, Schema, String
 from ..node import Node, is_node
@@ -171,8 +171,10 @@ def test_node_field_only_lazy_type_wrong():
 
 
 def test_str_schema():
-    assert str(schema) == dedent(
-        '''
+    assert (
+        str(schema).strip()
+        == dedent(
+            '''
         schema {
           query: RootQuery
         }
@@ -213,4 +215,5 @@ def test_str_schema():
           ): MyNode
         }
         '''
+        ).strip()
     )
diff --git a/graphene/relay/tests/test_node_custom.py b/graphene/relay/tests/test_node_custom.py
index 76a2cad3..762e3424 100644
--- a/graphene/relay/tests/test_node_custom.py
+++ b/graphene/relay/tests/test_node_custom.py
@@ -1,6 +1,6 @@
-from graphql import graphql_sync
+from textwrap import dedent
 
-from graphene.tests.utils import dedent
+from graphql import graphql_sync
 
 from ...types import Interface, ObjectType, Schema
 from ...types.scalars import Int, String
@@ -54,8 +54,10 @@ graphql_schema = schema.graphql_schema
 
 
 def test_str_schema_correct():
-    assert str(schema) == dedent(
-        '''
+    assert (
+        str(schema).strip()
+        == dedent(
+            '''
         schema {
           query: RootQuery
         }
@@ -93,6 +95,7 @@ def test_str_schema_correct():
           ): Node
         }
         '''
+        ).strip()
     )
 
 
diff --git a/graphene/test/__init__.py b/graphene/test/__init__.py
index 8591dc06..13b05dd3 100644
--- a/graphene/test/__init__.py
+++ b/graphene/test/__init__.py
@@ -1,5 +1,4 @@
 from promise import Promise, is_thenable
-from graphql.error import format_error as format_graphql_error
 from graphql.error import GraphQLError
 
 from graphene.types.schema import Schema
@@ -7,7 +6,7 @@ from graphene.types.schema import Schema
 
 def default_format_error(error):
     if isinstance(error, GraphQLError):
-        return format_graphql_error(error)
+        return error.formatted
     return {"message": str(error)}
 
 
diff --git a/graphene/tests/utils.py b/graphene/tests/utils.py
deleted file mode 100644
index b9804d9b..00000000
--- a/graphene/tests/utils.py
+++ /dev/null
@@ -1,9 +0,0 @@
-from textwrap import dedent as _dedent
-
-
-def dedent(text: str) -> str:
-    """Fix indentation of given text by removing leading spaces and tabs.
-    Also removes leading newlines and trailing spaces and tabs, but keeps trailing
-    newlines.
-    """
-    return _dedent(text.lstrip("\n").rstrip(" \t"))
diff --git a/graphene/types/definitions.py b/graphene/types/definitions.py
index 908cc7c8..e5505fd3 100644
--- a/graphene/types/definitions.py
+++ b/graphene/types/definitions.py
@@ -7,7 +7,6 @@ from graphql import (
     GraphQLObjectType,
     GraphQLScalarType,
     GraphQLUnionType,
-    Undefined,
 )
 
 
@@ -50,7 +49,7 @@ class GrapheneEnumType(GrapheneGraphQLType, GraphQLEnumType):
                 try:
                     value = enum[value]
                 except KeyError:
-                    return Undefined
+                    pass
         return super(GrapheneEnumType, self).serialize(value)
 
 
diff --git a/graphene/types/schema.py b/graphene/types/schema.py
index 0c6d4183..bf76b36d 100644
--- a/graphene/types/schema.py
+++ b/graphene/types/schema.py
@@ -376,19 +376,11 @@ class TypeMap(dict):
     def resolve_type(self, resolve_type_func, type_name, root, info, _type):
         type_ = resolve_type_func(root, info)
 
-        if not type_:
-            return_type = self[type_name]
-            return default_type_resolver(root, info, return_type)
-
         if inspect.isclass(type_) and issubclass(type_, ObjectType):
-            graphql_type = self.get(type_._meta.name)
-            assert graphql_type, f"Can't find type {type_._meta.name} in schema"
-            assert (
-                graphql_type.graphene_type == type_
-            ), f"The type {type_} does not match with the associated graphene type {graphql_type.graphene_type}."
-            return graphql_type
+            return type_._meta.name
 
-        return type_
+        return_type = self[type_name]
+        return default_type_resolver(root, info, return_type)
 
 
 class Schema:
diff --git a/graphene/types/tests/test_enum.py b/graphene/types/tests/test_enum.py
index 6e204aa9..471727c0 100644
--- a/graphene/types/tests/test_enum.py
+++ b/graphene/types/tests/test_enum.py
@@ -251,19 +251,22 @@ def test_enum_types():
 
     schema = Schema(query=Query)
 
-    assert str(schema) == dedent(
-        '''\
-        type Query {
-          color: Color!
-        }
+    assert (
+        str(schema).strip()
+        == dedent(
+            '''
+            type Query {
+              color: Color!
+            }
 
-        """Primary colors"""
-        enum Color {
-          RED
-          YELLOW
-          BLUE
-        }
-    '''
+            """Primary colors"""
+            enum Color {
+              RED
+              YELLOW
+              BLUE
+            }
+            '''
+        ).strip()
     )
 
 
@@ -345,10 +348,7 @@ def test_enum_resolver_invalid():
 
     results = schema.execute("query { color }")
     assert results.errors
-    assert (
-        results.errors[0].message
-        == "Expected a value of type 'Color' but received: 'BLACK'"
-    )
+    assert results.errors[0].message == "Enum 'Color' cannot represent value: 'BLACK'"
 
 
 def test_field_enum_argument():
@@ -460,12 +460,13 @@ def test_mutation_enum_input_type():
 
     schema = Schema(query=Query, mutation=MyMutation)
     result = schema.execute(
-        """ mutation MyMutation {
-        createPaint(colorInput: { color: RED }) {
-            color
+        """
+        mutation MyMutation {
+            createPaint(colorInput: { color: RED }) {
+                color
+            }
         }
-    }
-    """
+        """
     )
     assert not result.errors
     assert result.data == {"createPaint": {"color": "RED"}}
diff --git a/graphene/types/tests/test_schema.py b/graphene/types/tests/test_schema.py
index fe4739c9..c03c81ba 100644
--- a/graphene/types/tests/test_schema.py
+++ b/graphene/types/tests/test_schema.py
@@ -1,7 +1,8 @@
-from graphql.type import GraphQLObjectType, GraphQLSchema
+from textwrap import dedent
+
 from pytest import raises
 
-from graphene.tests.utils import dedent
+from graphql.type import GraphQLObjectType, GraphQLSchema
 
 from ..field import Field
 from ..objecttype import ObjectType
@@ -43,8 +44,10 @@ def test_schema_get_type_error():
 
 def test_schema_str():
     schema = Schema(Query)
-    assert str(schema) == dedent(
-        """
+    assert (
+        str(schema).strip()
+        == dedent(
+            """
         type Query {
           inner: MyOtherType
         }
@@ -53,6 +56,7 @@ def test_schema_str():
           field: String
         }
         """
+        ).strip()
     )
 
 
diff --git a/setup.py b/setup.py
index b06702be..dce6aa6c 100644
--- a/setup.py
+++ b/setup.py
@@ -84,8 +84,8 @@ setup(
     keywords="api graphql protocol rest relay graphene",
     packages=find_packages(exclude=["examples*"]),
     install_requires=[
-        "graphql-core~=3.1.2",
-        "graphql-relay>=3.0,<4",
+        "graphql-core>=3.1,<3.3",
+        "graphql-relay>=3.1,<3.3",
         "aniso8601>=8,<10",
     ],
     tests_require=tests_require,